Rivas Raúl, Willems Anne, Palomo José Luis, García-Benavides Pablo, Mateos Pedro F, Martínez-Molina Eustoquio, Gillis Monique, Velázquez Encarna
Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.
Laboratorium voor Microbiologie, Vakgroep Biochemie, Fysiologie en Microbiologie, Universiteit Gent, K. L. Ledeganckstraat 35, B-9000 Gent, Belgium.
Int J Syst Evol Microbiol. 2004 Jul;54(Pt 4):1271-1275. doi: 10.1099/ijs.0.02971-0.
Some varieties of sugar beet, Beta vulgaris, cultivated in northern Spain have large deformations that resemble the tumours produced by Agrobacterium species. In an attempt to isolate the agent responsible for these deformations, several endophytic slow-growing bacterial strains were isolated, the macroscopic morphology of which resembled that of Bradyrhizobium species. These strains were not able to produce tumours in Nicotiana tabacum plants and, based on phylogenetic analysis of their 16S rRNA, they are closely related to the genus Bradyrhizobium. Phenotypic and molecular characteristics of these strains revealed that they represent a species different from all Bradyrhizobium species previously described. Sequence analysis of the 16S-23S rDNA intergenic spacer region indicated that these novel strains form a homogeneous group, related to Bradyrhizobium japonicum, Bradyrhizobium liaoningense and Bradyrhizobium yuanmingense. DNA-DNA hybridization confirmed that these strains represent a novel species of the genus Bradyrhizobium, for which the name Bradyrhizobium betae sp. nov. is proposed. The type strain is PL7HG1T (=LMG 21987T=CECT 5829T).
在西班牙北部种植的一些甜菜品种（Beta vulgaris）有类似土壤杆菌属物种产生的肿瘤的大变形。为了分离造成这些变形的病原体，分离出了几种内生的生长缓慢的细菌菌株，其宏观形态类似于慢生根瘤菌属物种。这些菌株不能在烟草植物中产生肿瘤，并且基于它们16S rRNA的系统发育分析，它们与慢生根瘤菌属密切相关。这些菌株的表型和分子特征表明它们代表一个不同于先前描述的所有慢生根瘤菌属物种的物种。16S - 23S rDNA基因间隔区的序列分析表明这些新菌株形成一个同质群体，与日本慢生根瘤菌、辽宁慢生根瘤菌和圆明慢生根瘤菌相关。DNA - DNA杂交证实这些菌株代表慢生根瘤菌属的一个新物种，为此提出了新种名为甜菜慢生根瘤菌（Bradyrhizobium betae sp. nov.）。模式菌株是PL7HG1T（=LMG 21987T=CECT 5829T）。
